Green Bay has sold out its wild-card playoff game against San Francisco, but are cheeseheads being too loyal for their own good?

Sunday evening’s contest against the 49ers could set an NFL record for frigid conditions — and possibly border on dangerous.

The Weather.com forecast is predicting a high temperature of five degrees below zero – yes, that’s the high – and a low of minus-20. Other meteorological models project the high in the positive single digits, with a low not exceeding minus-10. The NFL doesn’t have a temperature reading that would force a postponement, NFL spokesman Brian McCarthy told ProFootballTalk.

Furthermore, the National Weather Service issued a wind chill advisory from 6 p.m. Central Saturday until 6 p.m. Central Sunday, right around the third quarter.

1967: Fans watch the Packers take on the Cowboys in the legendary Ice Bowl.Photo: AP

After that, the advisory becomes a warning: “Frost bite on exposed skin could occur within 30 minutes Saturday and Sunday. … And as little as 10 minutes Sunday night through Tuesday morning.”

The Packers will provide hand warmers (packets that fit inside gloves and stay warm for hours) and coffee to their frosty fans.

The coldest NFL game temperature of minus-13 degrees from “The Ice Bowl” played Dec. 31, 1967, in Green Bay featuring the Packers and Dallas Cowboys for the NFL championship. The second coldest game, with recorded temperatures of minus-9, was played Jan. 10, 1982, at Cincinnati’s Riverfront Stadium between the Bengals and San Diego Chargers for the AFC title.

The Giants march to the Super Bowl following the 2007 season included playing fifth-coldest game in NFL history when they beat the Packers at Lambeau Field in the NFC Championship game. Though the thermometer only read minus-4, the wind-chill factor brought it to minus-24.

Cold comfort for the hardy Wisconsinites: At least there’s no precipitation anticipated Sunday.